Metarhizium are major models for studying virulence evolution (host switching and speciation).

They are found ubiquitously in soils (plant roots and insects).

They have complicated interactions with plants that boost plant growth.

They might be developed as comprehensive plant-growth-promoting agents.

Broad host-range Metarhiziums have a high level of genome plasticity.

Metarhizium spp. mediate multiple interactions that are usually positive with respect to their long-term plant environment, and negative with respect to short-lived hosts. In particular, their ability to kill a wide range of insects maximizes protection to the plants and provides a resource of nitrogen that the fungus trades with the plant for carbon. Here, we highlight emerging concepts underlying Metarhizium–plant–insect interactions. Experiments on model systems have provided detailed mechanistic knowledge of how these fungi interact with plants and insects, and a greater understanding of the evolutionary forces driving these interactions. However, further integration of studies at the ecological and mechanistic level is needed to evaluate the importance of Metarhizium’s multitrophic interactions to the structuring of natural communities.

© 2022 Elsevier Ltd. All rights reserved.